net/rds/send.c

   1 /*
   2  * Copyright (c) 2006 Oracle.  All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  *
  32  */
  33 #include <linux/kernel.h>
  34 #include <linux/moduleparam.h>
  35 #include <linux/gfp.h>
  36 #include <net/sock.h>
  37 #include <linux/in.h>
  38 #include <linux/list.h>
  39 #include <linux/ratelimit.h>
  40 #include <linux/export.h>
  41
  42 #include "rds.h"
  43
  44 /* When transmitting messages in rds_send_xmit, we need to emerge from
  45  * time to time and briefly release the CPU. Otherwise the softlock watchdog
  46  * will kick our shin.
  47  * Also, it seems fairer to not let one busy connection stall all the
  48  * others.
  49  *
  50  * send_batch_count is the number of times we'll loop in send_xmit. Setting
  51  * it to 0 will restore the old behavior (where we looped until we had
  52  * drained the queue).
  53  */
  54 static int send_batch_count = 64;
  55 module_param(send_batch_count, int, 0444);
  56 MODULE_PARM_DESC(send_batch_count, " batch factor when working the send queue");
  57
  58 static void rds_send_remove_from_sock(struct list_head *messages, int status);
  59
  60 /*
  61  * Reset the send state.  Callers must ensure that this doesn't race with
  62  * rds_send_xmit().
  63  */
  64 void rds_send_reset(struct rds_connection *conn)
  65 {
  66         struct rds_message *rm, *tmp;
  67         unsigned long flags;
  68
  69         if (conn->c_xmit_rm) {
  70                 rm = conn->c_xmit_rm;
  71                 conn->c_xmit_rm = NULL;
  72                 /* Tell the user the RDMA op is no longer mapped by the
  73                  * transport. This isn't entirely true (it's flushed out
  74                  * independently) but as the connection is down, there's
  75                  * no ongoing RDMA to/from that memory */
  76                 rds_message_unmapped(rm);
  77                 rds_message_put(rm);
  78         }
  79
  80         conn->c_xmit_sg = 0;
  81         conn->c_xmit_hdr_off = 0;
  82         conn->c_xmit_data_off = 0;
  83         conn->c_xmit_atomic_sent = 0;
  84         conn->c_xmit_rdma_sent = 0;
  85         conn->c_xmit_data_sent = 0;
  86
  87         conn->c_map_queued = 0;
  88
  89         conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
  90         conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
  91
  92         /* Mark messages as retransmissions, and move them to the send q */
  93         spin_lock_irqsave(&conn->c_lock, flags);
  94         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
  95                 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
  96                 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
  97         }
  98         list_splice_init(&conn->c_retrans, &conn->c_send_queue);
  99         spin_unlock_irqrestore(&conn->c_lock, flags);
 100 }
 101
 102 static int acquire_in_xmit(struct rds_connection *conn)
 103 {
 104         return test_and_set_bit(RDS_IN_XMIT, &conn->c_flags) == 0;
 105 }
 106
 107 static void release_in_xmit(struct rds_connection *conn)
 108 {
 109         clear_bit(RDS_IN_XMIT, &conn->c_flags);
 110         smp_mb__after_clear_bit();
 111         /*
 112          * We don't use wait_on_bit()/wake_up_bit() because our waking is in a
 113          * hot path and finding waiters is very rare.  We don't want to walk
 114          * the system-wide hashed waitqueue buckets in the fast path only to
 115          * almost never find waiters.
 116          */
 117         if (waitqueue_active(&conn->c_waitq))
 118                 wake_up_all(&conn->c_waitq);
 119 }
 120
 121 /*
 122  * We're making the conscious trade-off here to only send one message
 123  * down the connection at a time.
 124  *   Pro:
 125  *      - tx queueing is a simple fifo list
 126  *      - reassembly is optional and easily done by transports per conn
 127  *      - no per flow rx lookup at all, straight to the socket
 128  *      - less per-frag memory and wire overhead
 129  *   Con:
 130  *      - queued acks can be delayed behind large messages
 131  *   Depends:
 132  *      - small message latency is higher behind queued large messages
 133  *      - large message latency isn't starved by intervening small sends
 134  */
 135 int rds_send_xmit(struct rds_connection *conn)
 136 {
 137         struct rds_message *rm;
 138         unsigned long flags;
 139         unsigned int tmp;
 140         struct scatterlist *sg;
 141         int ret = 0;
 142         LIST_HEAD(to_be_dropped);
 143
 144 restart:
 145
 146         /*
 147          * sendmsg calls here after having queued its message on the send
 148          * queue.  We only have one task feeding the connection at a time.  If
 149          * another thread is already feeding the queue then we back off.  This
 150          * avoids blocking the caller and trading per-connection data between
 151          * caches per message.
 152          */
 153         if (!acquire_in_xmit(conn)) {
 154                 rds_stats_inc(s_send_lock_contention);
 155                 ret = -ENOMEM;
 156                 goto out;
 157         }
 158
 159         /*
 160          * rds_conn_shutdown() sets the conn state and then tests RDS_IN_XMIT,
 161          * we do the opposite to avoid races.
 162          */
 163         if (!rds_conn_up(conn)) {
 164                 release_in_xmit(conn);
 165                 ret = 0;
 166                 goto out;
 167         }
 168
 169         if (conn->c_trans->xmit_prepare)
 170                 conn->c_trans->xmit_prepare(conn);
 171
 172         /*
 173          * spin trying to push headers and data down the connection until
 174          * the connection doesn't make forward progress.
 175          */
 176         while (1) {
 177
 178                 rm = conn->c_xmit_rm;
 179
 180                 /*
 181                  * If between sending messages, we can send a pending congestion
 182                  * map update.
 183                  */
 184                 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
 185                         rm = rds_cong_update_alloc(conn);
 186                         if (IS_ERR(rm)) {
 187                                 ret = PTR_ERR(rm);
 188                                 break;
 189                         }
 190                         rm->data.op_active = 1;
 191
 192                         conn->c_xmit_rm = rm;
 193                 }
 194
 195                 /*
 196                  * If not already working on one, grab the next message.
 197                  *
 198                  * c_xmit_rm holds a ref while we're sending this message down
 199                  * the connction.  We can use this ref while holding the
 200                  * send_sem.. rds_send_reset() is serialized with it.
 201                  */
 202                 if (!rm) {
 203                         unsigned int len;
 204
 205                         spin_lock_irqsave(&conn->c_lock, flags);
 206
 207                         if (!list_empty(&conn->c_send_queue)) {
 208                                 rm = list_entry(conn->c_send_queue.next,
 209                                                 struct rds_message,
 210                                                 m_conn_item);
 211                                 rds_message_addref(rm);
 212
 213                                 /*
 214                                  * Move the message from the send queue to the retransmit
 215                                  * list right away.
 216                                  */
 217                                 list_move_tail(&rm->m_conn_item, &conn->c_retrans);
 218                         }
 219
 220                         spin_unlock_irqrestore(&conn->c_lock, flags);
 221
 222                         if (!rm)
 223                                 break;
 224
 225                         /* Unfortunately, the way Infiniband deals with
 226                          * RDMA to a bad MR key is by moving the entire
 227                          * queue pair to error state. We cold possibly
 228                          * recover from that, but right now we drop the
 229                          * connection.
 230                          * Therefore, we never retransmit messages with RDMA ops.
 231                          */
 232                         if (rm->rdma.op_active &&
 233                             test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
 234                                 spin_lock_irqsave(&conn->c_lock, flags);
 235                                 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
 236                                         list_move(&rm->m_conn_item, &to_be_dropped);
 237                                 spin_unlock_irqrestore(&conn->c_lock, flags);
 238                                 continue;
 239                         }
 240
 241                         /* Require an ACK every once in a while */
 242                         len = ntohl(rm->m_inc.i_hdr.h_len);
 243                         if (conn->c_unacked_packets == 0 ||
 244                             conn->c_unacked_bytes < len) {
 245                                 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 246
 247                                 conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
 248                                 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
 249                                 rds_stats_inc(s_send_ack_required);
 250                         } else {
 251                                 conn->c_unacked_bytes -= len;
 252                                 conn->c_unacked_packets--;
 253                         }
 254
 255                         conn->c_xmit_rm = rm;
 256                 }
 257
 258                 /* The transport either sends the whole rdma or none of it */
 259                 if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
 260                         rm->m_final_op = &rm->rdma;
 261                         ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
 262                         if (ret)
 263                                 break;
 264                         conn->c_xmit_rdma_sent = 1;
 265
 266                         /* The transport owns the mapped memory for now.
 267                          * You can't unmap it while it's on the send queue */
 268                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
 269                 }
 270
 271                 if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
 272                         rm->m_final_op = &rm->atomic;
 273                         ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
 274                         if (ret)
 275                                 break;
 276                         conn->c_xmit_atomic_sent = 1;
 277
 278                         /* The transport owns the mapped memory for now.
 279                          * You can't unmap it while it's on the send queue */
 280                         set_bit(RDS_MSG_MAPPED, &rm->m_flags);
 281                 }
 282
 283                 /*
 284                  * A number of cases require an RDS header to be sent
 285                  * even if there is no data.
 286                  * We permit 0-byte sends; rds-ping depends on this.
 287                  * However, if there are exclusively attached silent ops,
 288                  * we skip the hdr/data send, to enable silent operation.
 289                  */
 290                 if (rm->data.op_nents == 0) {
 291                         int ops_present;
 292                         int all_ops_are_silent = 1;
 293
 294                         ops_present = (rm->atomic.op_active || rm->rdma.op_active);
 295                         if (rm->atomic.op_active && !rm->atomic.op_silent)
 296                                 all_ops_are_silent = 0;
 297                         if (rm->rdma.op_active && !rm->rdma.op_silent)
 298                                 all_ops_are_silent = 0;
 299
 300                         if (ops_present && all_ops_are_silent
 301                             && !rm->m_rdma_cookie)
 302                                 rm->data.op_active = 0;
 303                 }
 304
 305                 if (rm->data.op_active && !conn->c_xmit_data_sent) {
 306                         rm->m_final_op = &rm->data;
 307                         ret = conn->c_trans->xmit(conn, rm,
 308                                                   conn->c_xmit_hdr_off,
 309                                                   conn->c_xmit_sg,
 310                                                   conn->c_xmit_data_off);
 311                         if (ret <= 0)
 312                                 break;
 313
 314                         if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
 315                                 tmp = min_t(int, ret,
 316                                             sizeof(struct rds_header) -
 317                                             conn->c_xmit_hdr_off);
 318                                 conn->c_xmit_hdr_off += tmp;
 319                                 ret -= tmp;
 320                         }
 321
 322                         sg = &rm->data.op_sg[conn->c_xmit_sg];
 323                         while (ret) {
 324                                 tmp = min_t(int, ret, sg->length -
 325                                                       conn->c_xmit_data_off);
 326                                 conn->c_xmit_data_off += tmp;
 327                                 ret -= tmp;
 328                                 if (conn->c_xmit_data_off == sg->length) {
 329                                         conn->c_xmit_data_off = 0;
 330                                         sg++;
 331                                         conn->c_xmit_sg++;
 332                                         BUG_ON(ret != 0 &&
 333                                                conn->c_xmit_sg == rm->data.op_nents);
 334                                 }
 335                         }
 336
 337                         if (conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
 338                             (conn->c_xmit_sg == rm->data.op_nents))
 339                                 conn->c_xmit_data_sent = 1;
 340                 }
 341
 342                 /*
 343                  * A rm will only take multiple times through this loop
 344                  * if there is a data op. Thus, if the data is sent (or there was
 345                  * none), then we're done with the rm.
 346                  */
 347                 if (!rm->data.op_active || conn->c_xmit_data_sent) {
 348                         conn->c_xmit_rm = NULL;
 349                         conn->c_xmit_sg = 0;
 350                         conn->c_xmit_hdr_off = 0;
 351                         conn->c_xmit_data_off = 0;
 352                         conn->c_xmit_rdma_sent = 0;
 353                         conn->c_xmit_atomic_sent = 0;
 354                         conn->c_xmit_data_sent = 0;
 355
 356                         rds_message_put(rm);
 357                 }
 358         }
 359
 360         if (conn->c_trans->xmit_complete)
 361                 conn->c_trans->xmit_complete(conn);
 362
 363         release_in_xmit(conn);
 364
 365         /* Nuke any messages we decided not to retransmit. */
 366         if (!list_empty(&to_be_dropped)) {
 367                 /* irqs on here, so we can put(), unlike above */
 368                 list_for_each_entry(rm, &to_be_dropped, m_conn_item)
 369                         rds_message_put(rm);
 370                 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
 371         }
 372
 373         /*
 374          * Other senders can queue a message after we last test the send queue
 375          * but before we clear RDS_IN_XMIT.  In that case they'd back off and
 376          * not try and send their newly queued message.  We need to check the
 377          * send queue after having cleared RDS_IN_XMIT so that their message
 378          * doesn't get stuck on the send queue.
 379          *
 380          * If the transport cannot continue (i.e ret != 0), then it must
 381          * call us when more room is available, such as from the tx
 382          * completion handler.
 383          */
 384         if (ret == 0) {
 385                 smp_mb();
 386                 if (!list_empty(&conn->c_send_queue)) {
 387                         rds_stats_inc(s_send_lock_queue_raced);
 388                         goto restart;
 389                 }
 390         }
 391 out:
 392         return ret;
 393 }
 394
 395 static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
 396 {
 397         u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 398
 399         assert_spin_locked(&rs->rs_lock);
 400
 401         BUG_ON(rs->rs_snd_bytes < len);
 402         rs->rs_snd_bytes -= len;
 403
 404         if (rs->rs_snd_bytes == 0)
 405                 rds_stats_inc(s_send_queue_empty);
 406 }
 407
 408 static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
 409                                     is_acked_func is_acked)
 410 {
 411         if (is_acked)
 412                 return is_acked(rm, ack);
 413         return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
 414 }
 415
 416 /*
 417  * This is pretty similar to what happens below in the ACK
 418  * handling code - except that we call here as soon as we get
 419  * the IB send completion on the RDMA op and the accompanying
 420  * message.
 421  */
 422 void rds_rdma_send_complete(struct rds_message *rm, int status)
 423 {
 424         struct rds_sock *rs = NULL;
 425         struct rm_rdma_op *ro;
 426         struct rds_notifier *notifier;
 427         unsigned long flags;
 428
 429         spin_lock_irqsave(&rm->m_rs_lock, flags);
 430
 431         ro = &rm->rdma;
 432         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
 433             ro->op_active && ro->op_notify && ro->op_notifier) {
 434                 notifier = ro->op_notifier;
 435                 rs = rm->m_rs;
 436                 sock_hold(rds_rs_to_sk(rs));
 437
 438                 notifier->n_status = status;
 439                 spin_lock(&rs->rs_lock);
 440                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 441                 spin_unlock(&rs->rs_lock);
 442
 443                 ro->op_notifier = NULL;
 444         }
 445
 446         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 447
 448         if (rs) {
 449                 rds_wake_sk_sleep(rs);
 450                 sock_put(rds_rs_to_sk(rs));
 451         }
 452 }
 453 EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
 454
 455 /*
 456  * Just like above, except looks at atomic op
 457  */
 458 void rds_atomic_send_complete(struct rds_message *rm, int status)
 459 {
 460         struct rds_sock *rs = NULL;
 461         struct rm_atomic_op *ao;
 462         struct rds_notifier *notifier;
 463         unsigned long flags;
 464
 465         spin_lock_irqsave(&rm->m_rs_lock, flags);
 466
 467         ao = &rm->atomic;
 468         if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
 469             && ao->op_active && ao->op_notify && ao->op_notifier) {
 470                 notifier = ao->op_notifier;
 471                 rs = rm->m_rs;
 472                 sock_hold(rds_rs_to_sk(rs));
 473
 474                 notifier->n_status = status;
 475                 spin_lock(&rs->rs_lock);
 476                 list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 477                 spin_unlock(&rs->rs_lock);
 478
 479                 ao->op_notifier = NULL;
 480         }
 481
 482         spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 483
 484         if (rs) {
 485                 rds_wake_sk_sleep(rs);
 486                 sock_put(rds_rs_to_sk(rs));
 487         }
 488 }
 489 EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
 490
 491 /*
 492  * This is the same as rds_rdma_send_complete except we
 493  * don't do any locking - we have all the ingredients (message,
 494  * socket, socket lock) and can just move the notifier.
 495  */
 496 static inline void
 497 __rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
 498 {
 499         struct rm_rdma_op *ro;
 500         struct rm_atomic_op *ao;
 501
 502         ro = &rm->rdma;
 503         if (ro->op_active && ro->op_notify && ro->op_notifier) {
 504                 ro->op_notifier->n_status = status;
 505                 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
 506                 ro->op_notifier = NULL;
 507         }
 508
 509         ao = &rm->atomic;
 510         if (ao->op_active && ao->op_notify && ao->op_notifier) {
 511                 ao->op_notifier->n_status = status;
 512                 list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
 513                 ao->op_notifier = NULL;
 514         }
 515
 516         /* No need to wake the app - caller does this */
 517 }
 518
 519 /*
 520  * This is called from the IB send completion when we detect
 521  * a RDMA operation that failed with remote access error.
 522  * So speed is not an issue here.
 523  */
 524 struct rds_message *rds_send_get_message(struct rds_connection *conn,
 525                                          struct rm_rdma_op *op)
 526 {
 527         struct rds_message *rm, *tmp, *found = NULL;
 528         unsigned long flags;
 529
 530         spin_lock_irqsave(&conn->c_lock, flags);
 531
 532         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
 533                 if (&rm->rdma == op) {
 534                         atomic_inc(&rm->m_refcount);
 535                         found = rm;
 536                         goto out;
 537                 }
 538         }
 539
 540         list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
 541                 if (&rm->rdma == op) {
 542                         atomic_inc(&rm->m_refcount);
 543                         found = rm;
 544                         break;
 545                 }
 546         }
 547
 548 out:
 549         spin_unlock_irqrestore(&conn->c_lock, flags);
 550
 551         return found;
 552 }
 553 EXPORT_SYMBOL_GPL(rds_send_get_message);
 554
 555 /*
 556  * This removes messages from the socket's list if they're on it.  The list
 557  * argument must be private to the caller, we must be able to modify it
 558  * without locks.  The messages must have a reference held for their
 559  * position on the list.  This function will drop that reference after
 560  * removing the messages from the 'messages' list regardless of if it found
 561  * the messages on the socket list or not.
 562  */
 563 static void rds_send_remove_from_sock(struct list_head *messages, int status)
 564 {
 565         unsigned long flags;
 566         struct rds_sock *rs = NULL;
 567         struct rds_message *rm;
 568
 569         while (!list_empty(messages)) {
 570                 int was_on_sock = 0;
 571
 572                 rm = list_entry(messages->next, struct rds_message,
 573                                 m_conn_item);
 574                 list_del_init(&rm->m_conn_item);
 575
 576                 /*
 577                  * If we see this flag cleared then we're *sure* that someone
 578                  * else beat us to removing it from the sock.  If we race
 579                  * with their flag update we'll get the lock and then really
 580                  * see that the flag has been cleared.
 581                  *
 582                  * The message spinlock makes sure nobody clears rm->m_rs
 583                  * while we're messing with it. It does not prevent the
 584                  * message from being removed from the socket, though.
 585                  */
 586                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 587                 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
 588                         goto unlock_and_drop;
 589
 590                 if (rs != rm->m_rs) {
 591                         if (rs) {
 592                                 rds_wake_sk_sleep(rs);
 593                                 sock_put(rds_rs_to_sk(rs));
 594                         }
 595                         rs = rm->m_rs;
 596                         sock_hold(rds_rs_to_sk(rs));
 597                 }
 598                 spin_lock(&rs->rs_lock);
 599
 600                 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
 601                         struct rm_rdma_op *ro = &rm->rdma;
 602                         struct rds_notifier *notifier;
 603
 604                         list_del_init(&rm->m_sock_item);
 605                         rds_send_sndbuf_remove(rs, rm);
 606
 607                         if (ro->op_active && ro->op_notifier &&
 608                                (ro->op_notify || (ro->op_recverr && status))) {
 609                                 notifier = ro->op_notifier;
 610                                 list_add_tail(&notifier->n_list,
 611                                                 &rs->rs_notify_queue);
 612                                 if (!notifier->n_status)
 613                                         notifier->n_status = status;
 614                                 rm->rdma.op_notifier = NULL;
 615                         }
 616                         was_on_sock = 1;
 617                         rm->m_rs = NULL;
 618                 }
 619                 spin_unlock(&rs->rs_lock);
 620
 621 unlock_and_drop:
 622                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 623                 rds_message_put(rm);
 624                 if (was_on_sock)
 625                         rds_message_put(rm);
 626         }
 627
 628         if (rs) {
 629                 rds_wake_sk_sleep(rs);
 630                 sock_put(rds_rs_to_sk(rs));
 631         }
 632 }
 633
 634 /*
 635  * Transports call here when they've determined that the receiver queued
 636  * messages up to, and including, the given sequence number.  Messages are
 637  * moved to the retrans queue when rds_send_xmit picks them off the send
 638  * queue. This means that in the TCP case, the message may not have been
 639  * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
 640  * checks the RDS_MSG_HAS_ACK_SEQ bit.
 641  *
 642  * XXX It's not clear to me how this is safely serialized with socket
 643  * destruction.  Maybe it should bail if it sees SOCK_DEAD.
 644  */
 645 void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
 646                          is_acked_func is_acked)
 647 {
 648         struct rds_message *rm, *tmp;
 649         unsigned long flags;
 650         LIST_HEAD(list);
 651
 652         spin_lock_irqsave(&conn->c_lock, flags);
 653
 654         list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
 655                 if (!rds_send_is_acked(rm, ack, is_acked))
 656                         break;
 657
 658                 list_move(&rm->m_conn_item, &list);
 659                 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 660         }
 661
 662         /* order flag updates with spin locks */
 663         if (!list_empty(&list))
 664                 smp_mb__after_clear_bit();
 665
 666         spin_unlock_irqrestore(&conn->c_lock, flags);
 667
 668         /* now remove the messages from the sock list as needed */
 669         rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
 670 }
 671 EXPORT_SYMBOL_GPL(rds_send_drop_acked);
 672
 673 void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
 674 {
 675         struct rds_message *rm, *tmp;
 676         struct rds_connection *conn;
 677         unsigned long flags;
 678         LIST_HEAD(list);
 679
 680         /* get all the messages we're dropping under the rs lock */
 681         spin_lock_irqsave(&rs->rs_lock, flags);
 682
 683         list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
 684                 if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
 685                              dest->sin_port != rm->m_inc.i_hdr.h_dport))
 686                         continue;
 687
 688                 list_move(&rm->m_sock_item, &list);
 689                 rds_send_sndbuf_remove(rs, rm);
 690                 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 691         }
 692
 693         /* order flag updates with the rs lock */
 694         smp_mb__after_clear_bit();
 695
 696         spin_unlock_irqrestore(&rs->rs_lock, flags);
 697
 698         if (list_empty(&list))
 699                 return;
 700
 701         /* Remove the messages from the conn */
 702         list_for_each_entry(rm, &list, m_sock_item) {
 703
 704                 conn = rm->m_inc.i_conn;
 705
 706                 spin_lock_irqsave(&conn->c_lock, flags);
 707                 /*
 708                  * Maybe someone else beat us to removing rm from the conn.
 709                  * If we race with their flag update we'll get the lock and
 710                  * then really see that the flag has been cleared.
 711                  */
 712                 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
 713                         spin_unlock_irqrestore(&conn->c_lock, flags);
 714                         continue;
 715                 }
 716                 list_del_init(&rm->m_conn_item);
 717                 spin_unlock_irqrestore(&conn->c_lock, flags);
 718
 719                 /*
 720                  * Couldn't grab m_rs_lock in top loop (lock ordering),
 721                  * but we can now.
 722                  */
 723                 spin_lock_irqsave(&rm->m_rs_lock, flags);
 724
 725                 spin_lock(&rs->rs_lock);
 726                 __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
 727                 spin_unlock(&rs->rs_lock);
 728
 729                 rm->m_rs = NULL;
 730                 spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 731
 732                 rds_message_put(rm);
 733         }
 734
 735         rds_wake_sk_sleep(rs);
 736
 737         while (!list_empty(&list)) {
 738                 rm = list_entry(list.next, struct rds_message, m_sock_item);
 739                 list_del_init(&rm->m_sock_item);
 740
 741                 rds_message_wait(rm);
 742                 rds_message_put(rm);
 743         }
 744 }
 745
 746 /*
 747  * we only want this to fire once so we use the callers 'queued'.  It's
 748  * possible that another thread can race with us and remove the
 749  * message from the flow with RDS_CANCEL_SENT_TO.
 750  */
 751 static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
 752                              struct rds_message *rm, __be16 sport,
 753                              __be16 dport, int *queued)
 754 {
 755         unsigned long flags;
 756         u32 len;
 757
 758         if (*queued)
 759                 goto out;
 760
 761         len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 762
 763         /* this is the only place which holds both the socket's rs_lock
 764          * and the connection's c_lock */
 765         spin_lock_irqsave(&rs->rs_lock, flags);
 766
 767         /*
 768          * If there is a little space in sndbuf, we don't queue anything,
 769          * and userspace gets -EAGAIN. But poll() indicates there's send
 770          * room. This can lead to bad behavior (spinning) if snd_bytes isn't
 771          * freed up by incoming acks. So we check the *old* value of
 772          * rs_snd_bytes here to allow the last msg to exceed the buffer,
 773          * and poll() now knows no more data can be sent.
 774          */
 775         if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
 776                 rs->rs_snd_bytes += len;
 777
 778                 /* let recv side know we are close to send space exhaustion.
 779                  * This is probably not the optimal way to do it, as this
 780                  * means we set the flag on *all* messages as soon as our
 781                  * throughput hits a certain threshold.
 782                  */
 783                 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
 784                         __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
 785
 786                 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
 787                 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
 788                 rds_message_addref(rm);
 789                 rm->m_rs = rs;
 790
 791                 /* The code ordering is a little weird, but we're
 792                    trying to minimize the time we hold c_lock */
 793                 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
 794                 rm->m_inc.i_conn = conn;
 795                 rds_message_addref(rm);
 796
 797                 spin_lock(&conn->c_lock);
 798                 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
 799                 list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
 800                 set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 801                 spin_unlock(&conn->c_lock);
 802
 803                 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
 804                          rm, len, rs, rs->rs_snd_bytes,
 805                          (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));
 806
 807                 *queued = 1;
 808         }
 809
 810         spin_unlock_irqrestore(&rs->rs_lock, flags);
 811 out:
 812         return *queued;
 813 }
 814
 815 /*
 816  * rds_message is getting to be quite complicated, and we'd like to allocate
 817  * it all in one go. This figures out how big it needs to be up front.
 818  */
 819 static int rds_rm_size(struct msghdr *msg, int data_len)
 820 {
 821         struct cmsghdr *cmsg;
 822         int size = 0;
 823         int cmsg_groups = 0;
 824         int retval;
 825
 826         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 827                 if (!CMSG_OK(msg, cmsg))
 828                         return -EINVAL;
 829
 830                 if (cmsg->cmsg_level != SOL_RDS)
 831                         continue;
 832
 833                 switch (cmsg->cmsg_type) {
 834                 case RDS_CMSG_RDMA_ARGS:
 835                         cmsg_groups |= 1;
 836                         retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
 837                         if (retval < 0)
 838                                 return retval;
 839                         size += retval;
 840
 841                         break;
 842
 843                 case RDS_CMSG_RDMA_DEST:
 844                 case RDS_CMSG_RDMA_MAP:
 845                         cmsg_groups |= 2;
 846                         /* these are valid but do no add any size */
 847                         break;
 848
 849                 case RDS_CMSG_ATOMIC_CSWP:
 850                 case RDS_CMSG_ATOMIC_FADD:
 851                 case RDS_CMSG_MASKED_ATOMIC_CSWP:
 852                 case RDS_CMSG_MASKED_ATOMIC_FADD:
 853                         cmsg_groups |= 1;
 854                         size += sizeof(struct scatterlist);
 855                         break;
 856
 857                 default:
 858                         return -EINVAL;
 859                 }
 860
 861         }
 862
 863         size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
 864
 865         /* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
 866         if (cmsg_groups == 3)
 867                 return -EINVAL;
 868
 869         return size;
 870 }
 871
 872 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
 873                          struct msghdr *msg, int *allocated_mr)
 874 {
 875         struct cmsghdr *cmsg;
 876         int ret = 0;
 877
 878         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 879                 if (!CMSG_OK(msg, cmsg))
 880                         return -EINVAL;
 881
 882                 if (cmsg->cmsg_level != SOL_RDS)
 883                         continue;
 884
 885                 /* As a side effect, RDMA_DEST and RDMA_MAP will set
 886                  * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
 887                  */
 888                 switch (cmsg->cmsg_type) {
 889                 case RDS_CMSG_RDMA_ARGS:
 890                         ret = rds_cmsg_rdma_args(rs, rm, cmsg);
 891                         break;
 892
 893                 case RDS_CMSG_RDMA_DEST:
 894                         ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
 895                         break;
 896
 897                 case RDS_CMSG_RDMA_MAP:
 898                         ret = rds_cmsg_rdma_map(rs, rm, cmsg);
 899                         if (!ret)
 900                                 *allocated_mr = 1;
 901                         break;
 902                 case RDS_CMSG_ATOMIC_CSWP:
 903                 case RDS_CMSG_ATOMIC_FADD:
 904                 case RDS_CMSG_MASKED_ATOMIC_CSWP:
 905                 case RDS_CMSG_MASKED_ATOMIC_FADD:
 906                         ret = rds_cmsg_atomic(rs, rm, cmsg);
 907                         break;
 908
 909                 default:
 910                         return -EINVAL;
 911                 }
 912
 913                 if (ret)
 914                         break;
 915         }
 916
 917         return ret;
 918 }
 919
 920 int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
 921                 size_t payload_len)
 922 {
 923         struct sock *sk = sock->sk;
 924         struct rds_sock *rs = rds_sk_to_rs(sk);
 925         struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
 926         __be32 daddr;
 927         __be16 dport;
 928         struct rds_message *rm = NULL;
 929         struct rds_connection *conn;
 930         int ret = 0;
 931         int queued = 0, allocated_mr = 0;
 932         int nonblock = msg->msg_flags & MSG_DONTWAIT;
 933         long timeo = sock_sndtimeo(sk, nonblock);
 934
 935         /* Mirror Linux UDP mirror of BSD error message compatibility */
 936         /* XXX: Perhaps MSG_MORE someday */
 937         if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
 938                 ret = -EOPNOTSUPP;
 939                 goto out;
 940         }
 941
 942         if (msg->msg_namelen) {
 943                 /* XXX fail non-unicast destination IPs? */
 944                 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
 945                         ret = -EINVAL;
 946                         goto out;
 947                 }
 948                 daddr = usin->sin_addr.s_addr;
 949                 dport = usin->sin_port;
 950         } else {
 951                 /* We only care about consistency with ->connect() */
 952                 lock_sock(sk);
 953                 daddr = rs->rs_conn_addr;
 954                 dport = rs->rs_conn_port;
 955                 release_sock(sk);
 956         }
 957
 958         /* racing with another thread binding seems ok here */
 959         if (daddr == 0 || rs->rs_bound_addr == 0) {
 960                 ret = -ENOTCONN; /* XXX not a great errno */
 961                 goto out;
 962         }
 963
 964         /* size of rm including all sgs */
 965         ret = rds_rm_size(msg, payload_len);
 966         if (ret < 0)
 967                 goto out;
 968
 969         rm = rds_message_alloc(ret, GFP_KERNEL);
 970         if (!rm) {
 971                 ret = -ENOMEM;
 972                 goto out;
 973         }
 974
 975         /* Attach data to the rm */
 976         if (payload_len) {
 977                 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
 978                 if (!rm->data.op_sg) {
 979                         ret = -ENOMEM;
 980                         goto out;
 981                 }
 982                 ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
 983                 if (ret)
 984                         goto out;
 985         }
 986         rm->data.op_active = 1;
 987
 988         rm->m_daddr = daddr;
 989
 990         /* rds_conn_create has a spinlock that runs with IRQ off.
 991          * Caching the conn in the socket helps a lot. */
 992         if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
 993                 conn = rs->rs_conn;
 994         else {
 995                 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
 996                                         rs->rs_transport,
 997                                         sock->sk->sk_allocation);
 998                 if (IS_ERR(conn)) {
 999                         ret = PTR_ERR(conn);
1000                         goto out;
1001                 }
1002                 rs->rs_conn = conn;
1003         }
1004
1005         /* Parse any control messages the user may have included. */
1006         ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
1007         if (ret)
1008                 goto out;
1009
1010         if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
1011                 printk_ratelimited(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
1012                                &rm->rdma, conn->c_trans->xmit_rdma);
1013                 ret = -EOPNOTSUPP;
1014                 goto out;
1015         }
1016
1017         if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
1018                 printk_ratelimited(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
1019                                &rm->atomic, conn->c_trans->xmit_atomic);
1020                 ret = -EOPNOTSUPP;
1021                 goto out;
1022         }
1023
1024         rds_conn_connect_if_down(conn);
1025
1026         ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1027         if (ret) {
1028                 rs->rs_seen_congestion = 1;
1029                 goto out;
1030         }
1031
1032         while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
1033                                   dport, &queued)) {
1034                 rds_stats_inc(s_send_queue_full);
1035                 /* XXX make sure this is reasonable */
1036                 if (payload_len > rds_sk_sndbuf(rs)) {
1037                         ret = -EMSGSIZE;
1038                         goto out;
1039                 }
1040                 if (nonblock) {
1041                         ret = -EAGAIN;
1042                         goto out;
1043                 }
1044
1045                 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
1046                                         rds_send_queue_rm(rs, conn, rm,
1047                                                           rs->rs_bound_port,
1048                                                           dport,
1049                                                           &queued),
1050                                         timeo);
1051                 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
1052                 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
1053                         continue;
1054
1055                 ret = timeo;
1056                 if (ret == 0)
1057                         ret = -ETIMEDOUT;
1058                 goto out;
1059         }
1060
1061         /*
1062          * By now we've committed to the send.  We reuse rds_send_worker()
1063          * to retry sends in the rds thread if the transport asks us to.
1064          */
1065         rds_stats_inc(s_send_queued);
1066
1067         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1068                 rds_send_xmit(conn);
1069
1070         rds_message_put(rm);
1071         return payload_len;
1072
1073 out:
1074         /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
1075          * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
1076          * or in any other way, we need to destroy the MR again */
1077         if (allocated_mr)
1078                 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);
1079
1080         if (rm)
1081                 rds_message_put(rm);
1082         return ret;
1083 }
1084
1085 /*
1086  * Reply to a ping packet.
1087  */
1088 int
1089 rds_send_pong(struct rds_connection *conn, __be16 dport)
1090 {
1091         struct rds_message *rm;
1092         unsigned long flags;
1093         int ret = 0;
1094
1095         rm = rds_message_alloc(0, GFP_ATOMIC);
1096         if (!rm) {
1097                 ret = -ENOMEM;
1098                 goto out;
1099         }
1100
1101         rm->m_daddr = conn->c_faddr;
1102         rm->data.op_active = 1;
1103
1104         rds_conn_connect_if_down(conn);
1105
1106         ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
1107         if (ret)
1108                 goto out;
1109
1110         spin_lock_irqsave(&conn->c_lock, flags);
1111         list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
1112         set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
1113         rds_message_addref(rm);
1114         rm->m_inc.i_conn = conn;
1115
1116         rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
1117                                     conn->c_next_tx_seq);
1118         conn->c_next_tx_seq++;
1119         spin_unlock_irqrestore(&conn->c_lock, flags);
1120
1121         rds_stats_inc(s_send_queued);
1122         rds_stats_inc(s_send_pong);
1123
1124         if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
1125                 rds_send_xmit(conn);
1126
1127         rds_message_put(rm);
1128         return 0;
1129
1130 out:
1131         if (rm)
1132                 rds_message_put(rm);
1133         return ret;
1134 }